JPS6356558B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an electronic musical instrument that generates a musical tone closer to a natural musical instrument without increasing the capacity of an envelope memory. Conventionally, as a method for easily generating natural instrument sounds in electronic musical instruments, a waveform for one cycle of the musical sound to be generated is stored in a ROM or the like.
There is a method of reading out the waveform of the ROM at a predetermined clock to generate a musical sound waveform, and then multiplying it by an envelope signal stored separately in advance. However, in reality, each natural instrument has a slightly different envelope, and the time it takes to generate a musical tone can be quite long. The problem is that a huge amount of capacity is required. Furthermore, it is known that the sound of a natural musical instrument usually has a particularly significant characteristic in its rising part. For this reason, a method can be considered in which only the envelope of the rising portion is stored in the envelope memory, and the envelope signal of a constant level is multiplied by the musical sound waveform for the steady portion. However, in this case, even if a sufficient natural musical instrument feel is obtained in the rising portion, there is a drawback that the natural musical instrument feeling is completely lost in the steady portion. In view of the above points, the present invention stores only characteristic parts of the envelope, such as the rising and falling parts of musical tones, in the envelope memory, and the stationary parts are filled to a certain extent by noise signals. By assigning a random envelope, it is possible to obtain a sound close to a natural instrument sound over the entire period from the rise of the musical note to the steady part, or from the steady part to the fall, without increasing the envelope memory capacity. It is something. The present invention will be described below based on the drawings, and unless otherwise specified, all signals are digital signals. FIG. 1 shows an embodiment of the present invention.
In FIG. 1, reference numeral 1 denotes a waveform generator, which generates a desired musical sound waveform by pressing a key or the like. In this embodiment, a device is used that constantly outputs the waveform of a natural musical instrument sound (for example, violin, trumpet, etc.) at a constant frequency. The specific configuration of the waveform generator 1 is a well-known structure such as memory readout, so a detailed explanation will be omitted. Reference numeral 2 denotes an envelope memory (envelope storage device), which stores envelope information corresponding to the musical sound waveform sent out by the waveform generator 1, from the rising portion of the musical tone to the steady-state portion. 3 is a noise generator.
4 is an envelope generator, which generates an envelope signal based on the envelope information from the envelope memory 2 and the noise signal from the noise generator 3. In this embodiment, an envelope signal is generated from the rise of the musical tone to the stationary portion based on the stored contents of the envelope memory 2, and after that, that is, after the musical tone reaches the stationary portion, the noise generator 3 is activated. An envelope signal is generated based on the generated noise signal. A multiplier 5 modulates the steady musical sound waveform output from the waveform generator 1 by multiplying it by an envelope signal output from the envelope generator 4. 6 is a digital/analog converter (hereinafter
(referred to as a DAC), which converts the digital musical tone signal obtained by the multiplier 5 into an analog musical tone signal. Next, the operation shown in FIG. 1 will be explained. When a request is made to generate a musical tone by pressing a key or the like, the waveform generator 1 constantly generates a predetermined musical sound waveform at a predetermined frequency. This situation is shown in Figure 2a. On the other hand, the envelope generator 2 also starts generating an envelope signal at the same time as the key is pressed. This envelope signal is multiplied by the musical waveform from the waveform generator 1 by the multiplier 5, and the output thereof is converted into an analog signal by the DAC 6 and output as a musical tone signal. FIG. 3 shows a specific embodiment of the envelope generator 4. In FIG. In Figure 3, 7 is a latch;
The control signal given to the C terminal is at high level, that is, 1
When this is the case, the envelope information given from the envelope memory 2 is held, and when it is at a low level, that is, 0, it is output as is. 8 is a gate, and the noise generator 3 is controlled by the control signal given to the C terminal.
Controls the opening and closing of the noise signal output by the That is, when the control signal is 1, the output of the noise generator 3 is sent out as is, and when the control signal is 0, 0 is output. Reference numeral 9 denotes a filter, which filters the noise signal output from the gate 8 into a low frequency band. In this example,
A low-pass filter with a cutoff frequency of approximately 6 Hz is used as the filter 9. 10 is a clock generator which generates an envelope memory 2 based on key presses.
an address signal for reading the memory contents of
Generates control signals for latch 7 and gate 8. An adder 11 adds the output of the latch 7 and the output of the gate 8 and outputs the result to the multiplier shown in FIG. Next, the operation of the envelope generator 4 shown in FIG. 3 will be explained. When generation of a musical tone is requested by pressing a key or the like, the clock generator 10 sends an address signal to the envelope memory 2 and 0 to the latch 7 and gate 8 as a control signal in response to the key pressing signal.
In this state, the output of the latch 7 is equal to the output of the envelope memory 2 since the signal applied to the C terminal is 0, and the output of the gate 8 is also 0. Therefore, the output of the adder is equal to the output of the envelope memory 3. This state is shown as a rising portion in FIGS. 2b to 2e. Next, after a certain period of time passes in this state, when t=To, the envelope information from the envelope memory 2 becomes saturated and enters the steady state region.
At this point, the clock generator 10 counts the time since the key was pressed, and the control signal from the clock generator 10 is inverted to 1. In this state, the latch 7 latches the envelope information that was given immediately before the control signal was inverted to 1, and the gate 8 outputs the noise signal from the noise generator 3. This noise signal is converted into a band noise signal of 6 Hz or less by a filter 9 and is applied to an adder 11 . Then, the adder 11 adds the output from the envelope memory 2 and the output from the filter 8, and outputs the addition result to the multiplier 5. This situation is shown in Figure 2b~
The stationary part is shown in e. The envelope signal from the envelope generator 4 (FIG. 2 d) obtained as described above and the musical sound waveform from the waveform generator 1 (FIG. 2 a) are combined into a multiplier 5.
The output signal is converted into an analog signal by the DAC 6 to obtain an analog tone signal. As described above, in the above embodiment, the envelope signal read out from the envelope memory is used for the rising portion, and the noise signal generated by the noise generator is used for the steady portion. Therefore, for the rising part of a musical tone, the envelope waveform can be freely created depending on the memory design, so it is possible to obtain something very close to a natural musical tone, and for the stationary part, subtle fluctuations can be caused by the noise signal. This makes the musical sound less mechanical and more natural. Furthermore, since the envelope memory only needs to be used for the rising edge of a musical tone, there is no need to increase its capacity compared to the conventional method. Figure 4 shows the envelope generator 4 in Figure 1.
This is another example. Components having the same functions as those in FIG. 3 are given the same reference numerals. In FIG. 4, 12 is a noise generator, which generates a noise signal to which a DC offset is applied. This offset is made equal to the last value of the envelope information generated by the envelope memory 2, that is, the value of the envelope memory output at time t=To in FIG. Reference numeral 13 denotes a selector, which outputs an input signal from either input A or input B according to the control signal input to the C terminal. In this embodiment, when the control signal is 0, input A is selected and when the control signal is 1, input B is selected and output. Next, the operation of the envelope generator 4 shown in FIG. 4 will be explained. Since the envelope memory 2 and clock generator 10 are exactly the same as those shown in FIG. 3, the clock generator 10 outputs 0 as a control signal to the selector 13 for a certain period of time after the key is pressed, as shown in FIG. 2e. Output. Therefore, the selector 13 outputs the input A as a signal, that is, the envelope information sent out by the envelope memory.
On the other hand, the noise generator 12 generates a noise signal to which an offset has been added, and the filter 9 modulates this to leave only the low frequency range, as in FIG. Therefore, there is no change in the output of the filter 9 for the offset. Therefore, the output of filter 9 in FIG. 4 is equal to the output of filter 9 in FIG. 3 plus the offset. Therefore, when the control signal is inverted to 1 at time t=To in Figure 2, the output of filter 9 is output from selector 13, and as a result, the output of selector 13 becomes equivalent to the adder output shown in Figure 2 d. . Note that the offset level added to the noise signal matches the level of the envelope memory 2 immediately before the selector 13 switches the output, so even if the selector 13 switches the output signal at t=To, the envelope signal does not change. Needless to say, the average level does not change. Also, in Figures 3 and 4, the outputs of the noise generators 3 and 12 are waved by the filter 9, but if a noise generator that generates only low-frequency noise is used, the filter can be omitted. Needless to say, it's okay. FIG. 5 shows a specific configuration of the noise generator 12. In FIG. 5, 14 to 22 are 1-bit flip-flops, and a total of 9 flip-flops constitute a 9-bit shift register. 23 is exclusive OR (E.R). The shift registers 14 to 22 and the E/R 23 constitute an M-sequence pseudo noise generator. Signals are output from the 1st, 6th, and 9th bits of this shift register, and 3-bit noise signals 01, 02, 0 are generated.
It is set at 3. Furthermore, noise signals 01, 02, 03
5-bit offset signals 04 to 08 are added to the signal to obtain an offset noise signal. Here, 0 is given as 04 to 07, and 1 is given as 08. Here, if the frequency of the clock signal applied to the shift registers 14 to 22 is lowered, the output will be 0.
1 to 03 change slowly but randomly, so even if this signal is input directly to the selector 13 without going through the filter 9 in FIG. 4, an effect similar to the circuit shown in FIG. 3 can be obtained. . By the way, in the above explanation, only the rising and steady parts of musical tones are explained, and the falling part is not mentioned. However, regarding the falling part, for example, as shown in FIG. The selector 2 is provided with a falling envelope generator 24 that generates a
5 to switch. That is, in FIG. 6, the selector 25 operates as shown in Table 1, and the envelope memory 2, filter 9,
Each output of the falling envelope generator 24 is switched.

[Table] Therefore, when the key is pressed and the key press signal becomes 1, the fourth
Similarly to the figure, a clock generator 10 sends an address signal to an envelope memory 2, and a selector 2.
Control signal 0 is sent to the CI terminal of 5. Since the key press signal is 1 and the control signal is 0, the selector 25 sends the input of the A terminal, that is, the output of the envelope memory, to the multiplier 5 in FIG. Then, after a certain period of time has elapsed and the control signal output from the clock generator 10 is inverted to 1, the output of the filter 9,
That is, the noise signal generated by the noise generator 12 is output to the multiplier. Next, when the key is released and the key press signal becomes 0, the selector 25 sends the C terminal, ie, the output of the falling envelope generator 24, to the multiplier. As described above, the envelope generator 4
generates envelope signals corresponding to the rise, steady portion, and fall of a musical tone. In the above embodiment, the envelope signal is multiplied by one waveform generator that generates a musical sound waveform, but if one envelope signal is generated by multiple waveform generators. Alternatively, envelope signals may be given in common, and the multiplication and addition may be performed on each of the envelope signals. In addition, a plurality of circuits each including a waveform generator 1, an envelope memory 2, a noise generator 3, an envelope generator 4, and a multiplier 5 are prepared in the configuration shown in FIG. It goes without saying that the frequencies may be made to be different from each other and to be an integral multiple of the frequency of the reference set, and the sum of the outputs of the multipliers of each set may be taken and output as a musical tone signal. As described above, the present invention stores part of the envelope information in the envelope storage device, and switches the information read from the envelope storage device and the noise signal from the noise generator, or
A desired envelope signal is generated by mixing, and this envelope signal is multiplied by a musical sound waveform generated by a waveform generator to obtain a desired musical tone signal. For this reason, an envelope storage device stores parts that are characteristic of natural musical sounds, such as the rise of a musical tone, and the rise part of a musical sound waveform is multiplied by an envelope signal read out from this envelope storage device.
After the musical waveform has completely risen and entered the stationary part, by superimposing and adding an envelope signal based on the noise signal, it can be reached from the rise to the stationary part without increasing the capacity of the envelope storage device. It is possible to give a natural-looking envelope over the entire period, and the output musical tone does not become a fixed, monotonous tone from the middle, and it is possible to create a mechanical sound that changes periodically. This has the excellent effect of not producing a harsh musical tone.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of an electronic musical instrument according to the present invention, Fig. 2 is an output waveform diagram of each part of Fig. 1, and Figs. 3 and 4 are concrete diagrams of the envelope generator in Fig. 1. Block diagram showing the configuration, No. 5
This figure is a block diagram showing a specific configuration of a noise generator, and FIG. 6 is a block diagram showing another embodiment of an electronic musical instrument according to the present invention. 1... Waveform generator, 2... Envelope storage device, 3... Noise generator, 4... Envelope generator, 5... Multiplier, 7... Latch, 8... Gate, 9... Filter, 10 ...clock generator,
11...Adder, 12...Noise generator, 13...
...Selector, 24...Envelope storage device, 2
5...Selector.

Claims (1)

[Claims] 1. A waveform generator that generates a predetermined musical sound waveform based on key presses, etc., an envelope storage device that stores envelope information corresponding to the musical sound waveform, a noise generator that generates random noise information, and key presses, etc. an envelope generator that generates an envelope signal based on the envelope information and the noise information, and a multiplier that multiplies the musical sound waveform and the envelope signal, and the envelope generator measures the time after a key is pressed. It has a measuring means, and based on the output of the measuring means, generates an envelope signal based on the envelope information before a certain time elapses after the key is pressed, and generates a fluctuation based on the envelope information and the noise information after the elapse of a certain time. An electronic musical instrument characterized in that the electronic musical instrument is an envelope generator that generates an envelope signal.